The subject matter disclosed herein relates to hot gas path temperature measurement.
When validating heat transfer predictions of, for example, hot gas path components of a gas turbine engine, there are several unknown variables. These include external boundary temperatures, external heat transfer coefficients, internal boundary temperatures, internal heat transfer coefficients and material thicknesses and thermal conductivities. That is, when temperatures alone are thought to be known, an analyst still may not have enough information to tune each of the other variables in order to assure temperature predictions are correct. Direct measurement of the gas temperature, however, allows the analyst to directly measure one of these unknown quantities. This is particularly useful in areas that exhibit film cooling where external boundary (film) temperatures are less well known.
Direct measurement of gas temperatures in gas turbine engines has previously been achieved by way of temperature sensors being fixed within base metal of hot gas path components. This requires drilling holes to add the instrumentation to the parts, which introduces stress concentrations that reduce part life. Moreover, the fixing process has often been intrusive and operations of the temperature sensors have generally required data acquisition systems with active monitoring.